iPhone contact fields may get deleted from the device
Posted by - NA - on 30 June 2009 04:32 PM
iPhone/iPod touch Contacts have fields for Custom and Other phone numbers and for Ringtone
If used, the device does not send these fields to the server.  The contact will be missing these fields when viewed on the server.

In addition, if a change is made to the contact on the server, it is synchronized back to the device. 
Since the contact change coming from the server does not contain the custom/other phone number fields, they are deleted on the device when the change is synchronized. Ringtone, however, is preserved on the device.